IHJPAS. 36 (3) 2023 28 This work is licensed under a Creative Commons Attribution 4.0 International License *Corresponding Author: israanassrullah@yahoo.com Abstract The current investigation concluded an anatomical study of the cultivated species Pelargonium graveolens L. 'Hér belong to the Geraniaceae family and which cultivated as an ornamental plant, fresh specimen were collected from different region in Baghdad ,the study vegetative parts (leaf, stem and petiole) in details ,the upper and lower epidermis of leaf and epidermis of stem also studied, ordinary epidermal cells and stomatal complexes studied in term of shapes and dimensions ,the result showed that stomatal in leaf and stem is anomocytic type, the cross sections of the vegetative parts prepared by microtome and free hand sectioning. The tissues of these parts include the number and the type of layers and thickness of each one , the result showed the presence of druses crystals in parenchyma cells of the petiole, stem and leaf. Vistur type of this organs also studied and it comprises of glandular and non-glandular trichomes which occur in different types and lengths. Keywords: Pelargonium, anatomical study, leaf, petiole, stem, indumentum. 1. Introduction Pelargonium graveolens L. 'Hér belongs to the Geraniaceae family and is a species known as rose- scented geranium. Genus Pelargonium has more than 200 species. It originated in South Africa, where over 700 varieties of cultivated Geranium exist [1]. The plant is erect, multi-branched shrub that grows up to 1.5 m and has a spread of 1 m. [2]. The young stems are villous to density villous and herbaceous, but they become glabrous and woody with age. The leaves are palmatipartite to pinnatisect with irregularly pinnatipartite segments and are soft to touch. The margins of the segments are more or less revolute. White to pinkish-purple flowers is borne in 3-7 flowered pseudo-umbels [3]. doi.org/10.30526/36.3.3105 Article history: Received 11 November 2022, Accepted 12 December 2022, Published in July 2023. Ibn Al-Haitham Journal for Pure and Applied Sciences Journal homepage: jih.uobaghdad.edu.iq Anatomical Study for Vegetative Organs of Pelargonium graveolens L.'Hér Cultivated in Iraq Marwan Noori Mohamed Education of College, Biology Department of University of ,thamiaH-Al Ibn Science Pure for Baghdad, Baghdad, Iraq. marwannoori888890@yahoo.com Israa Kareem Nassrullah * Department of Biology, College of Education for Pure Science Ibn Al-Haitham, University of Baghdad, Baghdad, Iraq. israanassrullah@yahoo.com https://creativecommons.org/licenses/by/4.0/ mailto:israanassrullah@yahoo.com http://en.uobaghdad.edu.iq/?page_id=15060 http://en.uobaghdad.edu.iq/?page_id=15060 http://en.uobaghdad.edu.iq/?page_id=15060 http://en.uobaghdad.edu.iq/?page_id=15060 mailto:marwannoori888890@yahoo.com mailto:marwannoori888890@yahoo.com http://en.uobaghdad.edu.iq/?page_id=15060 http://en.uobaghdad.edu.iq/?page_id=15060 mailto:%20israanassrullah@yahoo.com mailto:israanassrullah@yahoo.com IHJPAS. 36 (3) 2023 29 The essential oil of Pelargonium graveolens has antifungal and antioxidant activity [4]. It also has antibacterial and insecticidal properties. The study of Jaradat et al. [5] demonstrates that this plant represents a rich source of bioactive substances that can be further investigated and authenticated for their medicinal potential. Boukhris et al. [6] demonstrated that administration of the essential oil of P. graveolens may be helpful in the prevention of diabetic complications associated with oxidative stress. Obeid and Jaber [7] studied the chemical composition and antioxidant activity of P. graveolens. Pelargonium species and related genera in Geraniaceae have been studied anatomically in many investigations, such as the study of Van der Walt and Demarne [3] for Pelargonium graveolens and P. radens in terms of their morphology and essential oils. The study included the trichomes in leaves, while Boukhris et al. [8] investigated the biological and anatomical characteristics of Pelargonium graveolens grown in the south of Tunisia, Salama et al. [9] studied the petiole and lamina of six species, including Pelargonium graveolens, which grows in Egypt; histo-anatomical studies on the vegetative and reproductive organs of Pelargonium roseum growing in Romania were conducted by Gâlea et al. [10]; Lancu et al. [11] also studied some Pelargonium species cultivated in Romania. The aim of this study is to describe anatomical features of vegetative organs for Pelargonium graveolens, which is cultivated in Baghdad, Iraq. 2. Materials and Methods Fresh specimens were collected from different regions in Baghdad, the upper and lower surface epidermis of blade leaf and stem were prepared by using stripping off using forcipes then transferred to a slide containing a drop of safranin -glycerine, then covered with a cover slide and examined under light microscope to study stomatal complex and ordinary epidermal cells [12]. The replica method was also used for taking imprints [13]. The stomatal index (%) was calculated according to the following formula: (S/S+E) ×100 where S and E are the numbers of stomata and epidermis, respectively, in the microscopic view field [14]. The cross sections of the stem, petiole, and leaf were prepared by microtome and hand sections and stained by toluidine blue, then examined under the microscope. The indumentum was also studied, and dimensions were determined by using an ocular micrometer. 3. Results Microscopic analysis of the surface epidermis of the leaf showed that the ordinary epidermal cells on the adaxial and abaxial surfaces had a polygonal shape, while their walls were undulate; the average dimension was (88.4 ×26) mm and (50.2 ×33.8) mm, respectively as shown in Table 1 and Figure 1. The leaf is amphistomatal and anomocytic, and the average dimensions of stomatal complexes were (37.7×26.3) mm and (30.3×29.2) mm in the upper and lower surfaces, respectively. The stomatal index varied in the upper and lower epidermis, reaching 8 in the upper epidermis and 29.2 in the lower epidermis (Table 1, Figuer1). The vertical section of the leaf showed that the blade leaf was bifacial, with a palisade layer on the upper side and a spongy layer on the lower side. The section of lamina consists of the upper epidermis (30) mm, which is covered by the cuticle (30) mm. The epidermis is followed by the mesophyll, which consists of the palisade layer and the spongy layer. The palisade layer is composed of one row of oblong cells, while the spongy layer is composed of 2-3 rows of cells IHJPAS. 36 (3) 2023 30 covered by the cuticle. Between two layers of mesophyll, there are parenchymatous cells containing drusen crystals, which are composed of calcium oxalate (Table 2, Figure 1). As shown in Table 3 and Figure 1, the midrib region has a semicircular outline. Collenchyma tissue and parenchyma tissue are located under the upper and lower epidermis. There are two central vascular bundles. The upper one is semicircular and smaller than the other vascular bundles, which are crescent-shaped (190.25123.06 mm). The thickness of xylem and phloem is 71.5 mm and 29.9 mm, respectively. The number of xylem columns is 24-28, and the number of xylem elements is 1-4. The petiole has a semicircular outline shape with a depression at the top of the section (Figure 2). It consists of the epidermis, covered by a toothed cuticle; the cortex located under the epidermis, which consists of one row of collenchyma, followed by 2-3 rows of chlorenchyma layers; the ordinary parenchyma layer follows the chlorenchyma layer, which also consists of 2-3 rows; druses crystal are found in this layer; beneath the parenchyma layer, there is a continuous ring of fiber, A vascular cylinder consists of 7-9 vascular bundles in a semi-triangular shape in three different sizes. The largest one in the top of the petiole, three medium-size bundles alternate with 3-5 small ones, and pith occupied the center of the petiole, which is composed of parenchyma cells (Table 4, Figure 2) The surface epidermis of the stem is composed of oblong-polygonal ordinary epidermal cells with straight, oblique walls. Stomata occur in the stem and its anomocytic type as well as in leaves, and the stomatal index reaches 3.77. (Table 5; Figure 3) Stem transverse section circular outline, anatomical structure form of epidermis composed of one row cells covered by toothed cuticle, cortex located below epidermis which consist of one row of collenchyma, 1-2 rows of chlorenchyma, 6-7 rows of parenchyma druses crystal found in this layer, fibers forms continuous ring above vascular cylinder which consist of 9-12 bundles in three different size , Keshavarzi et al.(2016) mentioned that the vascular bundles in stem occur in different size, vascular bundle compose of phloem and xylem, cambium obvious between phloem and xylem, this agreement with Gâlea et al. (2017), pith occupied the center of stem consist of parenchyma cell. (table 6; figure 4) Indumentum concluded that both glandular and non glandular hairs of different types, as follows, were observed in different vegetative parts: Unicellular non glandular hairs occur in all vegetative parts of the plant at different average lengths (414.75) mm in the leaf, (255.5) mm in the petiole, and (346.5) mm in the stem) (Table 7, Figure 5-A). Multicellular non glandular hairs formed by two cells are observed in the leaf at two different lengths (378) mm and (647) mm. (Table 7, Figure 5-B) Multicellular, non glandular hairs formed by 3–4 cells occur in the stem, their length reaching (895.62) mm. (Table 7, Figure 5-C) Glandular trichomes have at the top a secretory cell covered with a cuticle. Below the cuticle, in the secretion of the cell, essential oils are decomposed into different types: Sessile glandular hairs occur in the leaf; the head diameter was (11.8) mm (Table 7, Figure 5-D). Stalked glandular hairs, the stalk composed of one cell, occur in the leaf; stalk length is 9.5 mm; and the head is semispherical. (Table 7, Figure 5-E), this hair was also observed in the stem; the stalk length was (12.13) mm. On the stem, there is the same type, but the hair has a narrow neck between the average lengths of the stalk (16.46) mm. (Table, Figure 5-F) IHJPAS. 36 (3) 2023 31 Stalked glandular hairs, stalk formed by 2-3 cells, the head having a spherical or irregular shape , stalk length reaching 47 mm (Table 7, Figure 5-G). 4. Discussion The ordinary epidermal cells on the adaxial and abaxial sides of the leaf had a polygonal shape. Salimpour et al. [15] reported in their study of ten species of Geranium in Iran that some species had the polygonal shape of epidermal cells. The result shows that the leaf is amphistomatal and anomocytic. This agrees with [16], [9], [10], [11], and [15]. The study showed the occurrence of druses crystals in parenchyma cells between the palisade layer and spongy, which are composed of calcium oxalate. This crystal was reported in the studies carried out by [9], [10], and [17]. The petiole cortex contains a chlorenchyma layer, and this agrees with the study of Marias [18]. She also noted that the presence of a chlorenchyma petiole is evidence of its participation in the photosynthesis process. The ordinary parenchyma layer follows the chlorenchyma layer, and druse crystals are found in this layer. This is also in agreement with Marias [18] and Galea et al. [10]: beneath the parenchyma layer, There is a continuous ring of fiber in the vascular cylinder, composed of 7-9 vascular bundles in semi-triangular shape in three different sizes, the largest one in the top of the petiole, and this agrees with Lancu et al. [11], three medium-sized bundles alternate with 3-5 small ones. Keshavarzi et al. [19] also refer to the variation in bundle size in the petiole. In the stem transverse section, fibers form a continuous ring above the vascular cylinder, which consists of 9–12 bundles in three different sizes. Keshavarzi et al. [19] mentioned that the vascular bundles in the stem occur in different sizes. Indumentum concluded both glandular and non glandular hairs in different types. Many researchers reported glandular and non glandular hairs in their investigations, such as [8, 15, 17, 19, 20, 21, 22, and 23]. The current study agrees with Boukhris et al. [8] in that the highest length of non glandular hairs was recorded on the stem. As superficial structures, non-glandular trichomes protect plant organs against multiple biotic and abiotic stresses. The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds, primarily flavonoids. Due to the diffuse deposition of phenolic in the cell walls, trichomes provide protection against UV-B radiation by behaving as optical filters, screening out wavelengths that could damage sensitive tissues [24] while glandular hair structures present external cells empty of essential oils. When the cuticle is destroyed, the essential oils are dispersed into the atmosphere, which is a phenomenon that plays an important role in the attraction of insects [8]. Thus, glandular trichomes constitute a chemical barrier that reduces leaf ozone uptake and toxicity [25] and [26]. IHJPAS. 36 (3) 2023 32 Table 1. Characters of surface epidermis of the leaf measured by micrometers (μm). Upper epidermis Lower epidermis Ordinary epidermal cells Stomatal complex Ordinary epidermal cells Stomatal complex Length Width Length Width Stomatal index Length Width Length Width Stomatal index 78-109 (88.9) 39-80.6 (56.7) 35.1-39 (37.7) 26-28.6 (26.8) 8 46.8-57.2 (50.26) 28.6- 41.6 (33.8) 28.6-31.2 (30.33) 23.6-29 (26) 27.58 Number brackets represent average Table 2. Characters of vertical section in the leaf (Lamina) measured by micrometers (μm). Cuticle thickness Epidermis thickness Palisade layer Spongy layer Upper surface Lower surface Upper surface Lower surface Thickness Rows Thickness Rows 4.9-5.2 (5.02) 7.2-7.8 (7.45) 26-36.4 (32.0) 16.9-26 (22.1) 54.6-59.8 (58) 1 65-68.9 (66.3) 2-3 Number brackets represent average Table 3. Characters of midrib region in the leaf measured by micrometers (μm). Collenchyma thickness Parenchyma thickness Central bundle Upper Lower Upper Lower Dimension Phloem thickness Xylem thickness Fiber thickness 25.7- 28.6 (27.6) 36.9-78 (51.1) 59.4-62.4 (59.8) 208-239 (225.3) 468-494 (485.3) 28.6-31.2 (30.33) 59.8-65 (63.2) 15.6-18.2 (17.33) Number brackets represent average IHJPAS. 36 (3) 2023 33 T a b le 4 . C h a ra c te rs o f c ro ss se c tio n in p e tio le , m e a su re d b y m ic ro m e te rs (μ m ). C u tic le th ic k n e ss 5 .2 -6 .5 (5 .8 ) N u m b e r b r a c k e ts r e p r e se n t a v e r a g e E p id e r m is th ic k n e ss 1 8 .2 -2 0 .8 (1 9 .3 ) C o lle n c h y m a th ic k n e ss 2 1 .3 -2 3 .4 (2 2 .6 ) C h lo r e n c h y m a th ic k n e ss 9 5 -1 0 4 (8 2 .3 3 ) P a r e n c h y m a th ic k n e ss 9 1 -1 3 0 (1 0 8 .3 ) N o . o f B u n d le s 7 -9 D im e n sio n 2 5 7 .4 -3 1 2 × 1 9 5 -2 8 6 (2 7 6 × 2 2 9 .6 ) F ib e r th ic k n e ss 2 8 .6 -3 9 (3 2 .9 ) P h lo e m th ic k n e ss 2 6 .4 6 .8 (3 9 ) V a sc u la r th ic k n e ss 4 3 .9 5 -5 2 (4 8 .3 ) X y le m th ic k n e ss 5 4 .2 -7 8 (6 9 .3 3 ) P ith d ia m e te r 7 3 5 -7 8 7 .5 (7 6 6 .5 ) IHJPAS. 36 (3) 2023 34 T a b le 5 . C h a ra c te rs o f c ro ss se c tio n in ste m , m e a su re d b y m ic ro m e te rs (μ m ). S to m a ta D im e n sio n 4 1 .6 -4 4 .2 × 4 1 0 .8 - 5 2 0 (4 2 .4 )× (2 6 .8 ) S to m a ta l in d e x 3 .7 7 O r d in a r y c e ll D im e n sio n 8 8 .4 -1 3 5 .2 × 1 3 - 1 8 .2 (1 0 7 .1 )× (1 5 ) C u tic le th ic k n e ss 4 .6 -5 .2 (4 .9 ) E p id e r m is th ic k n e ss 2 1 .9 -2 3 .4 (2 2 .2 7 ) C o lle n c h y m a T h ic k n e ss 2 7 .8 -3 0 (2 8 8 ) R o w s 1 C h lo r e n c h y m a T h ic k n e ss 4 4 .2 -7 0 .2 (6 6 .5 ) T h ic k n e ss 2 0 3 P a r e n c h y m a T h ic k n e ss 1 8 2 -2 0 8 -1 9 3 .2 6 R o w s 6 -8 IHJPAS. 36 (3) 2023 35 Table 6. Characters of cross section in stem, measured by micrometers (μm). Bundle Fiber thickness Phloem thickness Vascular cambium thickness Xylem thickness Pith diameter Dimensions No. 364-416 ×410.8- 520 (394.3)×(449.9) 9-12 52-104 (69.33) 62.4-69.74 (67.6) 52-57.2 (53.8) 208-239 (217.5) 1260-1365 (1323) Number brackets represent average Table 7. Trichome characters measured by micrometer Organ Hair types Petiole Leaf Stem A-Unicellular eglandular length 199.5-367.5 (255.5) 336-441(414.7) 309-367.5 (346.5) B-Multicellular eglandular 2 cells, length, - (315-399) 378 (577.5-688.5) 647 - A- Multicellular 3-4 cells,length - 71.9-75.6 (74.2) 724.5-1.029 (895.6) D-Sessile glandular hairs, head diameters - 9.1-11.7 (11.18) - E- Stalked glandular hairs stalk cell , stalk length 14-65 (47.45) (7.8-10.4) (9.5) 10.9-17.5 (12.13) F- Stalked gland Stalk with neck - - 13-18.2 (16.4) G-Stalked glandular hairs, stalk 2-3 cells 41.6- 65 (47.45) - - The number between brackets represent average IHJPAS. 36 (3) 2023 36 Upper surface Lower surface Figure 1. Characters of leaf: A and B surface epidermis 400x, C: Lamina, D: vein region. 100x A B IHJPAS. 36 (3) 2023 37 Figure 2. Cross section of Petiole .A -40X, B and C-400X, ,D-100X A IHJPAS. 36 (3) 2023 38 Figure 3. Cross section of stem.A-40X ,B-D-400X, E-100X Druses crystal Cuticle C D A B IHJPAS. 36 (3) 2023 39 Figure 4. Trichomes of Pelargonium graveolens A, B, C: Non glandular hairs 100X, D-G: Glandular hairs 400X. A B C D D E F G IHJPAS. 36 (3) 2023 40 5. Conclusion The result obtained by the study showed the importance of anatomical structure to P. graveolens as a medicinal plant. The study concluded that the surface epidermis of leaf and stem, and cross section of stem, petiole,petiole and leaf, besides glandular and non glandular hairs that have a relation to the production of volatile oil, especially glandular ones, druse crystals appear in different regions of the studied organs. References 1. Pandey, P.; Upadhyay, R.K.; Singh,V.R.; Padalia, R.C.; Kumar, R.; Venkatesha, K.T.; Tiwari, A.K.; Singh, S.; Tewari, S.K. Pelargonium graveolens L. (Rose –scented geranium) : New hope for doubling Indian farmers income. Environ. Conserv. J., 2020, 21(1&2), 141-146. 2. Kochhar, S.L. 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